Rolling mill system



Feb. 20, 1968 F" J. BARNIKEL ROLLING MILL SYSTEM Filed July 16, 1965 3 Sheets-Sheet l PETER J. BARNIKEL BY NMHIML W Dmc-zum,

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ROLLING MILL SYSTEM 5 Sheets-Sheet :2

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INVENTOR. PETER J. BARNIKEL.

ATTORNEYS Feb. 20, 1968 P. J. BARNIKEL 3,369,383

ROLLI NC- MILL SYSTEM his AHORA/EVS United States Patent O 3,369,383 RULLING MILL SYSTEM Peter J. Barnikel, New London, Conn., assignor to General Dynamics Corporation, New York, N.Y., a corporation of Delaware Filed .Iuly 16, 1965, Ser. No. 472,637 16 Claims. (Cl. 72-237) ABSTRACT F THE DISCLOSURE In the particular embodiments of the invention described herein, the passline of a material being rolled in a rolling mill is maintained at a constant height by causing Variations in the size of the gap between the working rollsA of the mill to be distributed equally on opposite sides of the passline. In addition, the gap between working rolls is maintained substantially constant by driving the chocks supporting the working rolls against rigid spacers on opposite sides with a force greater than the roll separating force resulting from rolling of a material.

In one embodiment, hydraulic pistons drive each chock toward the rigid spacer and the frame in which the rolls are supported is suspended at the plane of the passline. In another embodiment, the chocks on one side of the working rolls are driven toward the rigid spacers by a piston and the chocks on the opposite side engage the frame, which is movable with respect to the spacers, the entire system being suspended from the spacers.

This invention relates to rolling mills, wherein the position of the passline may be maintained substantially free of extraneous variations from a reference datum despite the presence of one or more factors which caused such variations to occur in the prior art. Examples of those factors are re-setting of the size of the roll gap, deflection of the roll constraining means by the changes in the separating forces generated by the material being rolled, and changing rolls and roll diameters.

This invention also relates to rolling mills, wherein the size of the roll gap or roll parting may be maintained substantially free of extraneous variations, due to deection of the roll constraining means by the changes in the separating forces generated by the material being rolled, as occur in the prior art.

In typical prior art mills for rolling bars, rods and the like, heavy cast housings are employed to constrain the roll separating forces. Hand-operated screwdown screws are used to adjust the upper roll, and a complex arrangement of steel wedges and concentric screws is tted into the base of the mill to permit adjustment of the lower roll. Both the wedges and the screwdown screws of the conventional mill must be adjusted to obtain the desired height of passline and roll parting for a given rolling schedule. Any re-adjustment of the parting with the screwdown screws, without a complementary rex-adjustment of the wedges, causes a shift in the pass line and may necessitate an adjustment in height of the mill entry guide in order to maintain proper guidance of the material being rolled into the gap between the rolls.

In prior art mills, it is common (as in the mills disclosed in U.S. Patents 1,821,166, 2,525,687, 2,909,717, 3,024,679 and 3,076,360) for one roll to be movable and the other xed relative to the housing, and for the separation forces on the rolls to be opposed by asymmetrical constraints on those rolls, i.e., an active or movable constraint on the movable roll and a passive or reactive constraint on the fixed roll. Moreover, it is common (as in the -mills disclosed in U.S. Patents 1,729,410 and 1,821,166, 2,525,687 and 2,909,717) for the constraining 3,369,383 parentesi-en 2o, 196s ICC forces to be coupled to the housing so as to stretch or otherwise deform it.

The asymmetry of the constraints and the coupling of the constraining forces to the housing are factors which serve alone or together to produce extraneous variations in the positioning of the passline of the roll gap or in the size of that gap. Such extraneous variations are undesirable in any kind of rolling mill and are particularly disadvantageons in a bar or rod mill wherein the passline should have an exact predetermined positional relation to the guide which feeds the stock to the mill, and wherein the gap size should be held to close tolerances.

It is, accordingly, an object of this invention to provide mill apparatus characterized by a passline which is f maintainable at a set predetermined constant position relative to a reference datum despite a change in roll diameter or roll parting or despite the presence of other conditions which have heretofore caused extraneous variations in the position of the passline.

Another object of this invention is to provide mill apparatus wherein extraneous variations in the size of the roll gap are minimized.

Still another object of this invention'is to provide mill apparatus wherein the size of the roll gap may conveniently be reset without any concomitant shifting of the passline.

These and other objects are realized according to the invention by providing a mill comprised of a support frame and of a pair of lateral rolls spaced apart by a transverse gap and each movable transversely relative to the frame. A force-exerting means is coupled to both rolls to operably exert on each roll a respective one of two transverse forces which are oppositely directed to urge the rolls towards each other. Each of those forces is an active force in the sense that it drives and urges advancement relative to the support frame of the corresponding roll in the direction towards the other roll. Moreover, the two forces are symmetrical in that both are of the same character and are exactly or approximately of equal value.

The urged advancement relative to the support frame of each roll towards the other is stopped by a pair of transverse spacer means which have a stiff compressive modulus and a small transverse extent, and which are `disposed on laterally opposite sides of the roll gap to be in opposed relation to the mentioned active forces. By stopping the urged advancement of each roll, the two spacer means serve to determine the passline location and to set the size of the roll gap. Because the active forces on the rolls which serve to constrain the roll separation forces developed during rolling are symmetrical and exactly or approximately equal in value, they do not produce a differential load on the transverse spacer means. Hence, there is no tendency to shift the spacer means.

In operation, the active constraining forces on the rolls are maintained at a value greater than the maximum normal value of the roll separating forces. In this way, variations in gap size caused by the roll separation forces are governed by the stiftc compressive modulus and small transverse extent of the spacer means so as to be minimized.

The combination of the described symmetrical constraining of the rolls and of the transverse spacer means permits a coupling of the spacer means to the support frame in such manner that the passline is set relative to the adjacent part of the frame at a predetermined referenced position which is maintainable despite a change in roll diameter or a resetting of the size of the roll gap. It follows that, by such coupling, the passline may be spaced from the base end of the frame (or from the bed of the frame) by a set distance which is likewise maintainable despite one or both of the mentioned changes. Further, by coupling the spacer means to the support frame in a manner which isolates the operating forces on the rolls from the portion of the frame connecting the base end thereof to the part thereof coupled to the spacer means, that frame portion is rendered free of stretching or other deformation by those forces. Hence, the set distance between the passline and the base end of the frame will be dimensionally stable so as to provide a passline which has a constant position relative to that base end.

As an aspect of the invention, the mentioned transverse spacer means may be made symmetrically adjustable in transverse dimension about the center line of the spacer means so as to permit resetting the size of the roll gap in a manner not requiring any further resetting to maintain the position of the passline.

For a better understanding of the invention, reference is made to the following description of exemplary embodiments thereof and to the accompanying drawings wherein:

FIGURE 1 is a schematic view in elevation of one side of a mill according to the invention;

FIGURE 2 is a schematic view in elevation of one side of a modification of the FIG. 1 mill;

yFIGURE 3 is a plan view (partly in cross-section) of a specific structure for the FIGURE 2 mill;

FIGURE 4 is a view in front elevation (and partly in cross-section) of the mill of FIGURE 3;

FIGURE 5 is a view in side elevation (and partly in cross-section) of the mill of FIGURE 3;

FIGURE 6 is an enlarged view in cross-section of the wedge-actuated spacer mechanism shown in FIGURE 4; and i FIGURE 7 is a further View in cross-section of a detail of the FIGURE 6 mechanism, the cross-section of FIG- URE 7 being taken as indicated by the arrows 7-7 in FIGURE 6.

Referring now to FIG. 1, a rolling mill 10 rests on a bed 11 and has laterally opposite sides of which the front or right side is shown and of which the left or rear side is concealed but is a duplicate of the front side. A pair of lateral rolls 12, 13 extend between the two sides of the stand and are spaced from each other by a transverse roll gap 14. The reduced diameter front ends 16 and 17 of the two rolls are each journaled in a respective one of a pair of roll chocks 18 and 19. Each of the roll chocks is movable up and down between two tie couplings 20 and 21 of a heavy duty load bearing frame 22 having cross heads 24 and 25 connected by the tie couplings. A hydraulic ram 26 is disposed between cross head 24 and roll chock 18, and a similar hydraulic ram Z7 is disposed between cross head and roll chock 19. The frame 22 and the rams 2d and 27 together provide the front part of a force-exerting means for actively and symmetrically constraining the two rolls.

Disposed between the roll chocks 1S and 19 is a transverse spacer means hich may be a single device, but which is shown as being comprised of two longitudinally separated devices 30 and 31 which are small in transverse dimension compared to, say, the roll chocks, and which have a stiff modulus of elasticity in compression. The spacers 30 and 31 are represented in FIG. l as being integral parts of the 1eadbearing frame 22. Alternatively, the spacers may be devices which are separate from frame 22, but which are securely attached thereto, either in a permanently fixed manner or in a manner permitting resetting of the spacers along the length of the frame. However secured, the spacers and their coupling to frame 22 are of a character to render the spacers free of transverse play relative to frame 22. While the spacers may be invariable in transverse dimension, it is desirable for the transverse dimension of each to be capable of being set by adjustment to different dimensional values in a manner which is preferably symmetrical about the center plane 32 of the two spacer devices.

The load-bearing frame 22 is connected by a pair of conventional mountings 35 and 36 to the upper parts 37 and 38 of a pair of uprights or stanchions 39 and 40 together providing the front half or subframel of a relatively light-weight support frame or housing 34 comprised of that front or right subframe and a duplicate hack or rear subframe (not shown). The base ends 41 and 42 of the stanchions 39 and 40 are atiixed to and supported by the bed 11 for the mill stand. Mountings 37 and 38 may have permanently fixed positions relative to the stanchions. Alternatively, the mountings may tbe capable of being set to different levels on the stanchions. The coupling provided by the mountings between load `bearing frame 22 and support frame 3d is of a -character to eliminate transverse play between the two frames and, thereby, between the support frame 34 and the spacers 30 and 31.

The rolls 12 and 13 are adapted to roll material or stock in, say, the form of a bar or rod 49 fed in the longitudinal direction by guide means (not shown) to the gap 14 between the rolls. The passline 50 is operably caused to coincide with the center plane 32 of the spacers 30 and 31 `by virtue of a symmetrical spacing by those spacers of the roll chocks and rolls about that center plane.

As earlier stated, the unshown back side of the mill is a duplicate in structure of the shown front side thereof.

The FIG. 1 mill operates as follows: before rolling begins, each of the rams 26 and 27 is actuated to exert an active force on the roll chock and roll inwards of that ram so as to drive the chock towards the spacers 30, 31 and the roll in that chock towards the other roll. Each of the ram forces is an active force in the sense that it produces a driving and urged advancement relative to frame 34 of the corresponding roll chock and roll in the direction towards the other chock and roll. That is, ram 26 drives and urges advancement of chock 18 and roll 12 relative to frame 34 in the direction towards roll 13, and ram 27 drives and urges advancement relative to frame 34 of chock 19 and roll 13 in the direction towards roll 12. Moreover, under the driving of the rams, each chock and each roll undergoes an actual advancement relative to frame 34 in an amount essentially equal to one-half the total compressive deformation induced in the transverse direction in spacers 30 and 31 by the ram forces.

The active forces developed `hy the rams and directed towards center plane 32 are distinguished from the force which would 'be exerted towards that center line by a passive element substituted for one of the rams. The force from such a passive element would be a passive force in the sense that it would arise from an urged or actual advancement or deection lrelative to frame 34 of the chock and roll corresponding to that element in the direction away from the other chock and roll and in that such force would merely resist a further amount of such advancement or deection rather than being productive of a driving and urged advancement relative to frame 34 of the corresponding chock and roll in the direction towards the other chock-rand roll.

Besides ybeing active forces, the two ram forces on the Chocks and rolls are symmetrical in the sense that they are of exactly or approximately equal value and are both of the same character in that both are yielding forces of constant value (a characteristic of the force from a hydraulic ram), The symmetry of the forces of the FIG. 1 mill is to be distinguished from the relation between forces which are equal and opposite but which are asymmetrical in that they are not of the same character. An example of what is meant `by asymmetrical forces are two opposite forces which are balanced under no rolling conditions but of which one is a yielding constant force from a ram and the other is produced by a screwdown screw or other resilient means so as to be capable of varying as a function of displacement. The use of asymmetrical roll loading aseasss forces of this sort would lead under rolling conditions to an extraneous variation relative to a reference datum of the passline.

A further property of the ram forces is that they are greater than the maximum normal lroll separation forces encountered during rolling. To have the inwardly directed active forces on the chocks and rolls exceed the normal roll separation forces is advantageous for reasons later explained.

in the course of exerting the described active forces on the choclts and rolls, the rams 26 and 27 reactively load the crossheads 2d and 255 to render the tie couplings 2t) and 2l in tension. Because the active forces on the spacers 3@ and 3l are equal and opposite and because the forces on crossheads 2d and 2' are coupled in opposition through ties 20 and 2li, the forces generated inside load-bearing frame 22 or iu the frame itself are seen by mountings 35 and 36 as having a net value of zero. Hence, the support frame 3d is isolated from those forces, and the support frame and mountings of the FG. 1 mill need only be strong enough to support the weight of the front and back load bearing frames and the components contained therein.

The spacer devices 3@ and 3l serve to stop the urged advancement relative to frame 34 of each of the roll choclrs so as to thereby stop the two rolls from further approach towards each other. In so stopping the chocks, the spacers are compressively deformed symmetrically about the centerline 32 so as to develop by the deformation a pair of oppositely directed outward reactive forces which oppose the inward active forces from the rams. Because the spacers have a stiff modulus of compression and are of relatively small transverse extent, the deformation thereof, which provides the reactive forces equal to the active forces, is a decrease in the transverse dimension of the spacers of small absolute value.

After the rolls of FG. l have been preloaded as described, the rolls are set into motion by conventional roll driving means (not shown). The piece of stock 49 is then fed into gap lll to be passed through it by the moving rolls and to be rolled yby those rolls to a desired shape and/or size. In the course of its passage through the gap, the rolled material develops roll separation forces which are exerted on the rolls to tend to spread them apart.

In the course of rolling operations, the FlG. l mill provides an essentially constant gap size and a constant passline in a manner as follows:

The reactive roll separation forces are additive with the reactive forces from the compressed spacers 3d and 3l to form resultant reactive forces opposing the active forces from rams 26 and 27. The resultant reactive force in each of the upward and downward directions is the sum of the spacer reactive force in that direction and the roll separation force in that direction. The two resultant reactive forces are constant lbecause they are equal and opposite to the active r'am forces which are constant. Because the two resultant reactive forces are constant, a progressive increase in the roll separation forces has the effect of progressively lightening the load on spacers 30 and 3l to permit those spacers to expand from the minimum transverse dimensions to which they were compressively deformed by pre-loading before the rolling operation began. Since, however, the spacers are characterized by a stiff modulus of compression and a relatively small transverse dimension, the expansion of the spacers in response to an increase of roll separation forces is so small as to produce only a very slight enlargement in the size of the gap ld. Of course, the expansion under increasing roll separation forces of the portions of the roll chocks between the roll axes and the spacers is a factor which must also be considered, but the chocks are so stiff in compression that such chock expansions have little or no effect on the size of the gap. Because the active forces from the rams Vare greater than the 6 maximum normal roll separation forces, neither `of the roll chocks can ordinarily lift away from the spacers.

Thus, by employing active symmetrical constraining forces on rolls held apart by spacer means having a stiff modulus of compression and a small transverse dimension, extraneous variations in roll gap size arising from the roll separation force variations are reduced to a much lower value than they would have if it were necessary to rely on the modulus of elasticity in tension of a relatively compliant frame to keep the rolls from spreading apart. In this connection, although the tie couplings 20 'and 21 are stretched in tension as a result of the preloading of the rolls by the ram forces, such tensile stretching of the tie couplings has no effect in the FIG. 1 mill upon the positioning of the roll chocks or rolls.

The spacers 3@ and 3l by their stopping action on roll chocks 15S and ll9 serve to reference rolls 12, 13 and their passline 50 to the centerplane 32 of the spacers and to make passline 50 coincident with that centerplane. Also, the transversely playless coupling of the spacers to frame 22 at set predetermined positions in relation thereof serves to reference centerplane 32 and, hence, passline 5t) relative to frame 22. That is, passline 5t) is set at a position relative to frame 22 which coincides with, say, the centerline of that frame and which position at that frame centerline is maintainable despite changes made in the roll diameter or setting of the roll gap size in the course of setting up the mill for dierent rolling schedules or under the roll separation forces.

In the FIGURE l stand the coupling of frame 22 in the plane of the passline, the center plane 32 of'sp'acers 39 and 3l, by transverse playless mountings 35 and 36 to stanchions 39 and itl of support frame 34, serves to reference frame 22 and, hence, passline `50 to the upper parts 37 and 3S of stanchions 39 and ttl of frame 3d. Passline 50 being coincident with the center plane 32 of spacers 3d and 3l and frame 22 being coupled in the plane of the passline by transverse playless mounting to stanchions 39 'and d@ of from 34, it follows that the passline 5l) is maintainable relative to its point of attachment on frame 34 despite changes made in the roll diameter or setting of the roll gap size in the course of setting up the mill for different rolling schedules or variations in the deflections of frame 22 caused by variations in the set preload force developed by rams 26 and 27.

The height line all is referenced to the b'ase ends 41 and 42 of stanchions 39 and 30 in the sense that such height line is at a calibrated height above the reference datum provided by those base ends. If the portion of the support frame between those base ends and the height marked -by line 60 were to be subjected to a transverse force arising out of the ram forces or the roll separation forces or a combination of both, then that frame portion would be stretched or otherwise deformed so as to cause an extraneous variation in the distance of passline S0 from the reference datum established by the base ends 4l, 42. In the FG. l mill, however, the forces opera'bly generated within load bearing frame 22 are isolated from the support frame so as to not cause any extraneous stretching or deformation thereof. While the mentioned portion of the support frame bears the weight of the load bearing frame 22 and the components contained therein, the Weight force is a constant force which does not produce any change in the dimension of that portion. Hence, the suppo1t frame is dimensionally stable under operating conditions so as to maintain the passline 5t) at a vertical height D above the base ends 41, 42 which is not characterized by any extraneous variation and which, therefore, renders the passline 50 constant in position relative to those base ends.

The coupling of frame 22 by transverse playless mountings to stanchions 39 and 40 of support frame 34 at some point other than the center plane 32 of spacers 30 and 3i introduces a source of variation to the location of passline 5d relative to the datum reference established 7 by base ends 41 and 42. The stretch in tie couplings 2t) and 21, which results from the application of the preload forces by rams 26 and 27, can cause a shift in the location of passline S relative to the datum of reference by an amount equal to the stretch of the tie couplings between the point of attachment to reference frame and the center plane 32 of spacers 30 and 31. During the rolling process the force applied to frame 22 by the action of rams 26 and 27 is essentially constant and no additional extraneous variations in passline location are introduced. It follows that the FIGURE l mill could be reduced to a simpler form by eliminating support frame 34 and attaching the base of frame 22 to the ground datum reference during rolling as long as the active preload forces exerted by rams 26 and 27 were maintained at constant value.

As earlier pointed out, the spacers 30 and 31 may be devices which are symmetrically adjustable in the transverse dimension about centerplane 32 to provide difterent settings for that transverse dimension of the spacers so as, thereby, to provide different settings for the size of the roll gap 14. Because of the symmetry of adjustment, a resetting of the size of the gap does not produce an extraneous variation in the height of passline 50 relative to the base ends 11 and 42.

The resetting of the gap size by adjustment of the spacers is facilitated by the fact that the pistons of the hydraulic ram float in the cylinders thereof. By virtue of so floating, the ram pistons automatically yield or advance to follow the spacer adjustment while, at the same time, the pistons maintain a constant pressure on the roll chocks and rolls.

Other advantages in the use of one or more hydraulic rams to actively and symmetrically load the rolls are that the ram means can be utilized to provide a roll release action (in, say, a manner somewhat analogous to that taught in U.S. Patent 3,101,636) when abnormally large roll separation forces occur. Further, the roll chocks and rolls can be easily freed for removal from frame 22 by hydraulic retraction of the one or more ram pistons, and the values of the constraining forces exerted by the rams on the rolls can be set or determined with a high degree of accuracy.

The FIG. 2 mill is similar in structure to that of FIG. 1 except in the respects now to be noted. First, the loadbearing frame 22 is not secured to the support frame 34 but, instead, is positionally floating relative to the support frame. Second, the ram 26 has been omitted, and the upper crosshead 241 of frame 22 bears directly against the roll chock 18. Third, the spacers 30 and 31 are directly coupled to the upper parts 37 and 38 of the support frame.

I n operation, the FIG. 2 mill is similar in operation to that of FIG. 1 except for the mode of applying the active symmetrical loading forces to the roll chocks and rolls. In the FIG. 2 mill, the ram 27 operates as before to exert an active force on the roll chock 19 and roll 13. The reactive loading impressed by ram 27 on the now floating load bearing frame 22 is, however, utilized to supply the active force exerted on the roll chock 18 and roll 12. That is, the downward force on crosshead 25 from ram 27 is transmitted through tie couplings 2t) and 21 to crosshead 24 to there be exerted on chock 18 and through that chock on roll 12. Since, the downward force from crosshead 24 drives and urges advancement relative to support frame 34 of the elements 18 and 12 in the direction towards elements 19 and 13, that downward force is an active force as hereinbefore defined.

Further, the downward force from crosshead 24 is symmetrical in the sense hereinbefore defined with the upward force from ram 27 because that downward force from crosshead 24 is of the same value and character as the downward force exerted by ram 27 on crosshead 25, and because the latter downward force is equal in value to and of the same yielding constant character as 8 the upward force exerted by ram 27 on chock 19 and roll 13.

Because the FIG. 2 mill employs only one hydraulic ram per load-bearing frame, it can be lower in cost and easier to operate than the FIG. l mill. Further, the FIG. 2 mill structure inherently eliminates the departure from symmetrical loading on the rolls which would arise in the FIG. l mill if, because of improper operation or for some other cause, the two rams of FIG. l were to provide unequal force outputs. Still further, the direct coupling in the FIG. 2 mill of the spacers 311 and 31 to the support frame 34 is a simplification of structure which minimizes the possibility of undue transverse play or de- -iiection relative to the support frame of the spacer elements. Because the FIG. 2 mill has the advantages just discussed in addition to all those characterizing the FIG. l mill, the FIG. 2 mill is preferred.

A specilic structure for the FIG. 2 mill is shown by FIGS. 3, 4 and 5. Referring to those last-named figures, the right or front subframe of the support frame for the mill is provided by a pair of longitudinally spaced U- channel uprights 161 and 102 disposed with the channels thereof facing outwardly. The uprights 1111, 102 are joined at their base ends to each other by an L-channel 103 beam with reinforcing webs 1114. A pair of I-channel beams 10S at the bottom (FIG. 4) of the subframes connects the uprights of the right subframe to the corresponding uprights of the left subframe. The two subframes are also connected by another pair of I-channel beams 106, 1116 directly above beams 165.

Disposed between the uprights 1511, 162 are a pair of transversely or vertically spaced roll checks 1157, 10S of which each is movable up and down in guideways formed on the inner side of the uprights. The chock 1117 provides a bearing for the reduced diameter right-hand end 1119 of an upper roll 111 disposed laterally between the right and left subframes of the mill. Chock 1118 likewise provides a bearing for the right hand reduced-diameter end 11@ of a lower roll 112 disposed between the two subframes to be spaced from the upper work roll by a transverse gap 113. The two chocks are separated by a spacer apparatus 11S of the following character.

An outer box-like casing 116 has longitudinally opposite sides received in mating rectangular grooves 117, 118 formed in the inner sides of the uprights 1111, 102 (FIG. 5). The casing lits closely within those grooves to be constrained from any transverse movement relative to the uprights. Lateral movement of the casing in the grooves is prevented by screws 119 passing longitudinally through the uprights into holes in the casing.

The portion of the casing 116 towards the rolls is divided (FIG. 3) by a bay 125 into longitudinally forward and rear sections126 and 127 of which each contains a respective one of two duplicate spacer mechanisms. As shown by FIGS. 4, 6 and 7, the mechanism in section 126 includes a central active wedge 13@ guided by keys 131 extending from the walls of section 126 into keyways 132 formed in longitudinally opposite sides of the wedge and bisected by the wedge center plane 133. Because the casing 116 of the spacer apparatus is fixed in all respects relative to the subframe formed of uprights 101 and 1112, the key and keyway coupling of wedge 1311 to casing section 126 provides guide support for the wedge at at least three points which are each referenced to the subframe to have a set predetermined position in relation thereto, and which are the three points hypothetically necessary to define a plane. In this manner, the center plane 133 of wedge 130 is constnained by the mentioned key-keyway coupling to coincide with a plane defined by the mentioned three points which is the plane of movement for the wedge, and which is referenced to the right subframe to have a translationally and angularly set predetermined position relative to that subframe and to be normal to the direction of spacing of the rolls 111 and 112. Besides so constraining the wedge center plane, the

mentioned guide coupling constrains the wedge so as to allow no movement thereof in its plane of movement other than laterally in the inward or outward direction.

Lateral movement of the wedge 130 in the casing section 126 is effected by a drive comprised of a worm 140 engaging a worm gear 141 coaxial with and in translationally and rotationally fixed relation with a ball nut 142. The nut 1412 encircles a ball screw 143 of which the forward end is threadedly received in a socket in the back end of the wedge. Rotation of the screw is prevented by its coupling with the wedge. As the worm 140 is rotated in one direction or the other, its engagement through ballbearings with the screw 143 produces lateral translational movement in the inward or outward direction of the screw and, therefore, of the wedge. The thrust incident to lateral movement of the screw and wedge is taken up by a pairof bearings 1135, 146 disposed at laterally opposite ends of the worm gear-ball nut combination.

The worm 140 in casing section 126 and the worm (not shown) in casing section 127 are coupled together (FIG. by a releasable coupling 150. When the two worms are linked together through the coupling, the separate spacer mechanisms in the two casing sections may be driven simultaneously by a shaft 151 rotated by the turning of a hand wheel 152. The coupling 150 may, however, be temporarily disconnected to permit independent lateral positioning of the separate active wedges in the two spacer mechanisms. Subsequently, the coupling 150 is reconnected. The releasable coupling thus permits the two spacer mechanisms in section 126 and section 127 to be driven together throughout a range of relative adjustment.

The drive shaft 151 for the two spacer mechanisms is connected by gearing 153 to (a) a mechanical counter 154 for registering the number of turns of handwheel 152 and, (b) a motor 155 which may be used in place of the wheel 152 te turn the shaft 151, and which motor is suitably mounted (by means not shown). The mechanical output to the counter 154 may, if desired, be supplied as an input to a device which senses angular displacement and which serves as a parting feedback device incorporated in a closed loop servo system for automatically controlling roll parting. Further details of a similar system are disclosed in copending application Serial No. 150,738 filed Nov. 7, 1961, and owned by the assignee hereof.

Returning to the details of the spacer mechanism in casing section 126, the double-sided active wedge 130 has transversely opposite upper and lower inclined wedge bearing faces 160 and 161 definitive of a dihedral angle bisected by the wedge center plane 133. Disposed over the upper wedge face 160 is a single sided passive wedge 162 received in a rectangular opening 163 (FIG. 3) in the top of casing section 126. The passive wedge 162 has lower and upper faces 164 and 165 which are parallel to, respectively, the face 160 of active wedge 130 and the center plane 133 of that active wedge. Since the mentioned center plane is normal to the transverse direction (i.e., the direction in spacing of rolls 111 and 112), the upper face 165 of wedge 162 is likewise normal to that transverse direction.

Friction between the wedge 130 and the wedge 162 is minimized by a sheet 166 of polytetralluoroethylene which is interposed between those wedges, and which may be of the character disclosed in the aforementioned application Serial No. 150,738 and in co-pending application Serial No. 405,749 led October 22, 1964. Longitudinally opposite ilaps 167 of the sheet 166 are folded upwardly and against the longitudinally opposite sides of the wedge 162 to till up the clearance between those sides and the corresponding sides of opening 163 so as to constrain wedge 162 from longitudinally moving within the opening. A pair of polytetraliuoroethylene shims 165 at laterally opposite ends of wedge 162 prevent lateral movement of the wedge within its opening. Hence, the passive wedge 10 162 is constrained so that it can move only transversely, i.e., vertically.

Disposed below active wedge 130 is another singlesided passive wedge 172 which projects through a lower opening 173 in casing 116, has an outer hearing face 175 parallel to wedge center plane 133i, is separated from center wedge 130 by a sheet of polytetraliuoroethylene 176 and is otherwise similar in configuration and constrain to the upper passive wedge 162. When lower chock is retracted from spacer apparatus 115, wedge 172 is prevented frorn falling through opening 173 by keeper pins 174 (FIG. 6) connected at their ends to the casing 116 of the spacer apparatus.

As the center wedge is moved laterally inward by its drive, the passive wedges 162 and 172 are wedged apart symmetrically about centerplane 133 so that their respective bearing faces and 175 each travel outward from that plane by an equal distance. Conversely, as wedge 1130 is moved laterally outward by its drive, the two passive wedges and their bearing faces 165 and 175 approach each other symmetrically about plane 133. Once the bearing faces 165 and 175 have been set to have a desired spacing, they are held at that spacing yby wedge 130 and its drive.

The spacer mechanisms in casing section 126 and casing section 127 are coupled (FIG. 5) to upper roll chock 107 through respective shims 180, and are coupled in like manner to the lower chock 108 through shims 181 (FIG. 6) of the same thickness as shims 100. As the rolls 111 and 112 wear down, and are ground to a lesser diameter, the original shims 100 and 181 are replaced by upper and lower shims which are of lesser thickness than the original shims but are of the same thickness as each other.

On the right side of the FIG. 3 mill, the upper and lower roll chocks are held apart a selected distance (determined by the thickness of shims 100, 101 and the setting of spacer apparatus 115) by virtue of urging those roll chocks towards plane 133 by force-exerting means of a nature as follows.

The pair of chocks 107, 108 is contained within a load bearing frame 159 comprised of an upper crosshead 190, a lower crosshead 101 and a pair of longitudinally-spaced tie bars 192 and 103 connected to the crossheads by pins 194 and disposed in the outward facing channels formed in the uprights 101 and 102. Frame 109 is positionally oating in the transverse direction relative to the support subframe comprised of uprights 101 and 102. The floating frame is, however, constrained from movement other than transverse translational movement by guide members which are disposed in the mentioned channels, and of which one such guide member 105 is shown in FIG. 4- in the channel formed in the forward upright of the left support subframe.

Disposed longitudinally between the bars 192, 193

(iF-IG. 5) and transversely between lower crosshead 191 and lower roll chock 108 is a hydraulic ram 200. The ram is comprised (FIG. 4) of a hydraulic cylinder 201 containing a piston 203 having a downward reduceddiameter end 204 positioned against the lower crosshead 191. Cylinder 201 is closed at its upper end by a thick circular plate 202 of which the rim projects radially outwards of the outside of the cylinder to form a first exterior flange for the ram. The lower end of a cylinder 201 is closed by another thick circular plate 206 having therein a central aperture 205 through which the ram end 204 passes. Plate 206 is coaxial with and of the same size as plate 202 to form a second exterior flange for ram 200. The two flange plates 202 and 206 are received (FIG. 5) in guideways 207 formed in the inner sides of uprights 101 and 102 to permit transverse movement of the ram but to constrain it from other than transverse movement. When the ram is idle, the weight of the ram and of lower roll chock 103 is taken by keeper blocks 203 secured to uprights 101 and 102 to be disl 1 posed beneath the salient flange portion of the upper ram closure plate 202.

Ram 260 is actuated by injection through a pipe 299 and a conduit 21h in plate 202 of pressurized hydraulic fluid into a main hydraulic chamber 211 above piston 203. Retraction of vthe piston is accomplished by injection through a pipe 212, and a conduit 213 in plate 2% of pressurized hydraulic fluid into an auxiliary annular' chamber 2li/i disposed in cylinder 261 below the pistonl 263 and around the downwardly extending piston end 21M.

When ram 29d is actuated, the resultant expanding of its transverse dimension urges roll chock 1% upward until the urged advancement of the chock relative to uprights itil and 102 is stopped by the bearing of the chock through shims 131 against the lower outer surfaces of the two sections 121' and 127 of spacer apparatus 11S. Simultaneously, the expanding ram urges lloating frame 189 downward to cause crosshead 19t? to impart to upper chock 1%7 an urged advancement downward which is stopped by the bearing of that chock through shims 180 against the upper outer surfaces of the mentioned two sections of the spacer apparatus 115. l

The left side of the FIG. 3 mill is, as stated, a duplicate in structure and operation of the previously described right hand side thereof. Those left and right elements which are counterparts are designated in the drawings by the same reference numeral but are distinguished from each other by using a prime sufiix with the reference numerals which designate the left elements. Unless the context otherwise requires, the description herein of elements on the right side of the FIG. 3 is to be taken as equally applicable to the left hand counterparts of those elements.

In the operation of the FIG. 3 mill, the left and right rams are actuated to push up against the left and right lower roll chocks and to pull down on the two load bearing frames so as to cause those frames to push down on the two upper chocks. The upper and lower chocks are thus urged together but are held apart by the stopping actions of the right and left spacer devices 115 land 115 to be separated by a distance which is determined by the settings of those devices and by the thickness of the shims between the spacer devices and the roll chocks. ln this manner, the work rolls 111 and 112 of the mill are symmetrically pre-loaded by active forces exceeding the maximum normal value of the roll separation forces expected to be encountered during rolling. Further, the rolls 111 and 112 are set apart by a gap 113 having a size determined by the settings of the spacer devices and the thickness of the mentioned shims, and having a passline which coincides with the center plane 133 of the spacer devices.

After the rolls have been pre-loaded, they are set into motion by conventional roll driving means (not shown). Stock, bar, or rod is then fed into the gap 113 to be passed through it by the motion of the rolls and to be rolled to a desired size and/ or shape during the passage. During a rolling operation, the FIG. 3 mill maintains a constant size of roll gap and a constant position for the passline of that gap in the manner described hereinbefore in connection with FIGS. 1 and 2. The size of the roll gap may be reset by resetting the spacer devices 115 and 11S either while the left and right rams are actuated or while they are unactuated. 1n between rolling operations, the pistons of the two rams may be retracted from operating position. When they are so retracted, the rams and lower chocks are supported by the keeper blocks on the two support subframes, and the load-bearing frames, upper chocks and upper rolls are supported by the left and right spacer devices which are in turn supported by the left and right support subframes.

The previously described embodiments are being exemplary only, it is to be understood that additions thereto, modifications thereof, and omissions therefrom can be made without departing from the spirit of the invention, and that the invention comprehends embodiments differing in form and/ or detail from those that have been specifically described. For example, the axes of the mill rolls may be either horizontal or vertical. Further, the FIG. l mill may be modified as hereinbefore described to eliminate the support frame by attaching the base of the constraining frame to the datum reference. ln addition, the FIG. 2 mill may be modified by inverting the hydraulic ram and attaching the transverse tie couplings of the constraining frame directly to the hydraulic ram and thus eliminating the lower crosshead. Further7 appropriately placed auxiliary hydraulic jacks or other devices may be employed to balance out any inequalities due to weight forces in the forces operably effective on the upper and lower rolls of the described mills. While the invention hereof is particularly useful in connection with -mills for rolling bars or rods, it is also of application in connection with other types of rolling mills, as, say, millsf or rolling plate or strip.

Accordingly, the invention is not to be considered as limited save as it is consonant with recitals of the following claims.

I claim:

1. A rolling mill comprising, a frame, a pair of lateral rolls transversely spaced by a gap, each roll being disposed in said frame for transverse motion in relation thereto, force-exerting means coupled to said rolls to drive and urge advancement of each roll relative to said frame in the direction towards the other roll by a respective one of two oppositely directed active symmetrical transverse forces, and a pair of transverse spacer means having greater rigidity than the frame disposed on laterally opposite sides of said gap in opposed relation to said driving forces to set the size of said gap by stopping advancement relative to said frame of each roll towards the other.

2. Apparatus as in claim 1 in which said force-exerting means is comprised of hydraulic ram means.

3. The method of rolling yby lateral rolls spaced by a transverse gap and disposed in a frame for transverse motion in relation thereto, said method comprising actively driving each of said rolls relative to said frame in the direction towards the other roll by a respective one of two oppositely directed active symmetrical transverse forces so as to urge advancement relative to said frame of each roll towards the other, setting the size of said gap by stopping actions exerted by relatively rigid spacer components on laterally opposite sides of said gap to set a limit to the urged advancement relative to said frame of each roll towards the other, passing material through said gap to be rolled by said rolls, and maintaining said forces during said rolling at a value greater than the maximum normal value of the separation forces exerted on said rolls by said material.

4. A rolling mill comprising, a frame, a pair of lateral rolls transversely spaced by a gap and disposed in said frame for transverse motion in relation to said frame, force-exerting means coupled to said rolls to drive and urge advancement of each roll relative to said frame in the direction towards the other roll by a respective one of two oppositely directed ac-tive symmetrical transverse forces, a pair of spacer means each transversely divided Iby a common lateral center plane and disposed on laterally opposite sides of said gap in opposed relation to said forces to stop advancement relative to said frame of each roll towards the other roll `so as to thereby set the size of said gap, and transversely playless coupling means by which said spacer means is coupled to said frame to reference the passline of said gap to said frame so as to have a set predetermined position relative t0 said frame, said passline position being maintainable despite a resetting of gap size.

5. Apparatus as in claim 4- in which said spacer means are symmetrically adjustable in transverse dimension about said centerline so as to provide for resetting of the size of said gap.

6. Apparatus as in claim 4 in which said forceexerting means is floating relative to said frame.

7. A rolling mill comprising, a `support frame having a base end, a pair of lateral rolls transversely spaced by a gap, each roll being disposed in said frame in transversely spaced relation from said end for transverse motion in relation to said frame, force-exerting means coupled to said rolls to drive and urge advancement of each roll relative to said frame in the direction towards the other roll by a respective one of two oppositely directed active symmetrical transverse forces, a pair of transverse spacer means disposed on laterally opposite sides of said gap in opposed relation to said driving forces to set the size of said gap by stopping advancement relative to said frame of each roll towards the other, and transversely playless coupling means by which said spacer means is coupled to said frame and by which said forces are isolated from said frame to maintain the passline of the gap between said stopped rolls at a dimensionally stable distance from said base end.

8. Apparatus as in claim 7 in which said force-exerting means comprises, force constraining frame means havingV transversely spaced lateral crossheads disposed on opposite transverse sides of said rolls and coupled together by tie couplings, and source means of said active forces disposed inside said frame means to develop said active symmetrical forces and to simultaneously reactively load said force constraining frame means.

9. Apparatus as in claim 7 in which said loadbearing frame means is positionally oating relative to said support means.

10. Apparatus as in claim 7 in which said source means of said active forces is wholly on one transverse side of said rolls and is coupled through said iloating load-bear ing frame means to the other transverse side of said rolls which is on the side away from said Source means.

11. A rolling mill comprising, left and right laterally spaced support subframe, a pair of lateral rolls disposed between said frames and spaced apart by a transverse gap, left and right sets of roll chocks for said rolls, left and right transverse spacer means carried by respectively, said left and right support subframes and disposed between, respectively, the chocks of said left set and the chocks of said right set, left and right force constraining frames for, respectively, said left chocks and said right chocks, and left and right force-exerting means of which each is operable on the corresponding force constraining frame and on the chocks associated with that frame to load such frame and to urge the chocks associated with that frame against opposite sides of the spacer means between those checks.

12. A rolling mill comprising, a pair of laterally spaced subframes, a pair of lateral rolls disposed between said frames and spaced apart by a transverse gap, roll chocks disposed adjacent each subframe for positioning said rolls, the chocks in each subframe being each movable in the transverse direction relative to the adjacent subframe, wedge-actuated transverse spacer means associated with each subframe and disposed between the roll chocks adjacent that frame to space such chocks apart by a variable spacing, each of said wedge-actuated means being comprised of active double sided wedge means movable relative to the adjacent subframe to effect said variable spacing, guide means aixed with each subfr-ame and providing for the associated active wedge means at least a three point guide support which constrains the center plane of such wedge means to coincide with a plane of wedge movement translationally and angularly referenced to that subframe to have a set prelil determined positional relation therewith, said plane of movement being normal to the transverse direction of spacing of said rolls, and wedge adjusting means to move each active wedge means to a selected position in the plane of movement therefor and to hold such wedge means at that position.

13. Apparatus as in claim 12 in which each active wedge means is definitive of a dihedral angle bisected by the center plane of said wedge means, and in which said center plane is positioned by said guide means to contain the passline of said roll gap.

14. Apparatus as in claim 12 in which each active Wedge remains is disposed between a pair of single sided passive wedge means which are wedgeab'le apart by said active means according to the adjustment thereof, and in which each of said passive wedge means has an outer bearing face parallel to the center plane of said active wedge means.

1S. Apparatus as in claim 12 in which the active wedge means associated with each subframe comprises a pair of double sided wedges spaced apart in the direction of passage of material through said roll gap, and in which the adjusting means for each such active wedge means comprises a separate adjusting mechanism for each of the two wedges thereof and, also, means releasably coupling said separate mechanisms for linked operation thereof when coupled together and forl independent adjustment thereof when released from each other.

16. A rolling mill comprising, left and right laterally spaced support subframes, a pair of lateral rolls disposed between said subframes and spaced apart by a transverse gap, left and right sets of roll chocks for said rolls, said left and right sets being adjacent to, respectively, said left and right subframes, and the chocks in each set being transversely variable in position relative to each other and to the adjacent frame, left and right wedge-actuated transverse spacer means carried by, respectively, said left and right :subframes so as to have coincident center planes which contain the passline of said gap and which are in translationally and angularly set positions referenced to said subframes, said left and right spacer means being inserted between, respectively, the chocks of said left set and those of said right set, and each of said spacer means having in the transverse direction a dimension which is determinative of the spacing between the chocks to either side thereof and which is symmetrically adjustable by wedge action about the passline of said gap, left and right force constraining frames for, respectively, said left and right sets of chocks, said left and right force constraining frames being positionally floating relative to, respectively, said left and right support subframes, and left `and right force-exerting means each operable on the corresponding force constraining frame and on the associated set of checks to load such frame and to apply oppositely directed active symmetrical forces on the separate choclrs of that set so as to urge each of those checks towards the intervening spacer means to be positioned by such spacer means.

References Cited UNITED STATES PATENTS 2,599,414 6/1952 Rodder 72-238 3,036,538 5/1962 Ottestad et al. 100--269 3,172,314 3/1965 Morgan et al. 72-237 3,194,045 7/ 1965 Hill 72-238 3,286,501 11/1966 Tracy 72-237 CHARLES W. LANHAM, Primary Examiner. A. RUDERMAN, Assistant Examiner. 

